/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  */
/*  SHA-256 implementation in JavaScript                (c) Chris Veness 2002-2014 / MIT Licence  */
/*                                                                                                */
/*  - see http://csrc.nist.gov/groups/ST/toolkit/secure_hashing.html                              */
/*        http://csrc.nist.gov/groups/ST/toolkit/examples.html                                    */
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  */

/* jshint node:true *//* global define, escape, unescape */
'use strict';


/**
 * SHA-256 hash function reference implementation.
 *
 * @namespace
 */
var Sha256 = {};


/**
 * Generates SHA-256 hash of string.
 *
 * @param   {string} msg - String to be hashed
 * @returns {string} Hash of msg as hex character string
 */
Sha256.hash = function(msg) {
  // convert string to UTF-8, as SHA only deals with byte-streams
  msg = msg.utf8Encode();

  // constants [§4.2.2]
  var K = [
    0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
    0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
    0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
    0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
    0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
    0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
    0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
    0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2 ];
  // initial hash value [§5.3.1]
  var H = [
    0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19 ];

  // PREPROCESSING

  msg += String.fromCharCode(0x80);  // add trailing '1' bit (+ 0's padding) to string [§5.1.1]

  // convert string msg into 512-bit/16-integer blocks arrays of ints [§5.2.1]
  var l = msg.length/4 + 2; // length (in 32-bit integers) of msg + ‘1’ + appended length
  var N = Math.ceil(l/16);  // number of 16-integer-blocks required to hold 'l' ints
  var M = new Array(N);

  for (var i=0; i<N; i++) {
    M[i] = new Array(16);
    for (var j=0; j<16; j++) {  // encode 4 chars per integer, big-endian encoding
      M[i][j] = (msg.charCodeAt(i*64+j*4)<<24) | (msg.charCodeAt(i*64+j*4+1)<<16) |
        (msg.charCodeAt(i*64+j*4+2)<<8) | (msg.charCodeAt(i*64+j*4+3));
    } // note running off the end of msg is ok 'cos bitwise ops on NaN return 0
  }
  // add length (in bits) into final pair of 32-bit integers (big-endian) [§5.1.1]
  // note: most significant word would be (len-1)*8 >>> 32, but since JS converts
  // bitwise-op args to 32 bits, we need to simulate this by arithmetic operators
  M[N-1][14] = ((msg.length-1)*8) / Math.pow(2, 32); M[N-1][14] = Math.floor(M[N-1][14]);
  M[N-1][15] = ((msg.length-1)*8) & 0xffffffff;


  // HASH COMPUTATION [§6.1.2]

  var W = new Array(64); var a, b, c, d, e, f, g, h;
  for (var i=0; i<N; i++) {

    // 1 - prepare message schedule 'W'
    for (var t=0;  t<16; t++) W[t] = M[i][t];
    for (var t=16; t<64; t++) W[t] = (Sha256.σ1(W[t-2]) + W[t-7] + Sha256.σ0(W[t-15]) + W[t-16]) & 0xffffffff;

    // 2 - initialise working variables a, b, c, d, e, f, g, h with previous hash value
    a = H[0]; b = H[1]; c = H[2]; d = H[3]; e = H[4]; f = H[5]; g = H[6]; h = H[7];

    // 3 - main loop (note 'addition modulo 2^32')
    for (var t=0; t<64; t++) {
      var T1 = h + Sha256.Σ1(e) + Sha256.Ch(e, f, g) + K[t] + W[t];
      var T2 =     Sha256.Σ0(a) + Sha256.Maj(a, b, c);
      h = g;
      g = f;
      f = e;
      e = (d + T1) & 0xffffffff;
      d = c;
      c = b;
      b = a;
      a = (T1 + T2) & 0xffffffff;
    }
    // 4 - compute the new intermediate hash value (note 'addition modulo 2^32')
    H[0] = (H[0]+a) & 0xffffffff;
    H[1] = (H[1]+b) & 0xffffffff;
    H[2] = (H[2]+c) & 0xffffffff;
    H[3] = (H[3]+d) & 0xffffffff;
    H[4] = (H[4]+e) & 0xffffffff;
    H[5] = (H[5]+f) & 0xffffffff;
    H[6] = (H[6]+g) & 0xffffffff;
    H[7] = (H[7]+h) & 0xffffffff;
  }

  return Sha256.toHexStr(H[0]) + Sha256.toHexStr(H[1]) + Sha256.toHexStr(H[2]) + Sha256.toHexStr(H[3]) +
    Sha256.toHexStr(H[4]) + Sha256.toHexStr(H[5]) + Sha256.toHexStr(H[6]) + Sha256.toHexStr(H[7]);
};


/**
 * Rotates right (circular right shift) value x by n positions [§3.2.4].
 * @private
 */
Sha256.ROTR = function(n, x) {
  return (x >>> n) | (x << (32-n));
};

/**
 * Logical functions [§4.1.2].
 * @private
 */
Sha256.Σ0  = function(x) { return Sha256.ROTR(2,  x) ^ Sha256.ROTR(13, x) ^ Sha256.ROTR(22, x); };
Sha256.Σ1  = function(x) { return Sha256.ROTR(6,  x) ^ Sha256.ROTR(11, x) ^ Sha256.ROTR(25, x); };
Sha256.σ0  = function(x) { return Sha256.ROTR(7,  x) ^ Sha256.ROTR(18, x) ^ (x>>>3);  };
Sha256.σ1  = function(x) { return Sha256.ROTR(17, x) ^ Sha256.ROTR(19, x) ^ (x>>>10); };
Sha256.Ch  = function(x, y, z) { return (x & y) ^ (~x & z); };
Sha256.Maj = function(x, y, z) { return (x & y) ^ (x & z) ^ (y & z); };


/**
 * Hexadecimal representation of a number.
 * @private
 */
Sha256.toHexStr = function(n) {
  // note can't use toString(16) as it is implementation-dependant,
  // and in IE returns signed numbers when used on full words
  var s='', v;
  for (var i=7; i>=0; i--) { v = (n>>>(i*4)) & 0xf; s += v.toString(16); }
  return s;
};


/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  */


/** Extend String object with method to encode multi-byte string to utf8
 *  - monsur.hossa.in/2012/07/20/utf-8-in-javascript.html */
if (typeof String.prototype.utf8Encode == 'undefined') {
  String.prototype.utf8Encode = function() {
    return unescape( encodeURIComponent( this ) );
  };
}

/** Extend String object with method to decode utf8 string to multi-byte */
if (typeof String.prototype.utf8Decode == 'undefined') {
  String.prototype.utf8Decode = function() {
    try {
      return decodeURIComponent( escape( this ) );
    } catch (e) {
      return this; // invalid UTF-8? return as-is
    }
  };
}


/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  */
if (typeof module != 'undefined' && module.exports) module.exports = Sha256; // CommonJs export
if (typeof define == 'function' && define.amd) define([], function() { return Sha256; }); // AMD

////////////////////////////////////////////////////////////////////
///////////// IdentityServer JS Code Starts here ///////////////////
////////////////////////////////////////////////////////////////////

function getCookies() {
  var allCookies = document.cookie;
  var cookies = allCookies.split(';');
  return cookies.map(function(value) {
    var parts = value.trim().split('=');
    if (parts.length === 2) {
      return {
        name: parts[0].trim(),
        value: parts[1].trim()
      };
    }
  }).filter(function(item) {
    return item && item.name && item.value;
  });
}

function getBrowserSessionId() {
  var cookies = getCookies().filter(function(cookie) {
    return (cookie.name === cookieName);
  });
  // empty string represents anonymous sid
  return (cookies[0] && cookies[0].value) || '';
}

/*! (c) Tom Wu | http://www-cs-students.stanford.edu/~tjw/jsbn/ */
var b64map = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
var b64pad = '=';

function hex2b64(h) {
  var i;
  var c;
  var ret = '';
  for (i = 0; i + 3 <= h.length; i += 3) {
    c = parseInt(h.substring(i, i + 3), 16);
    ret += b64map.charAt(c >> 6) + b64map.charAt(c & 63);
  }
  if (i + 1 == h.length) {
    c = parseInt(h.substring(i, i + 1), 16);
    ret += b64map.charAt(c << 2);
  }
  else if (i + 2 == h.length) {
    c = parseInt(h.substring(i, i + 2), 16);
    ret += b64map.charAt(c >> 2) + b64map.charAt((c & 3) << 4);
  }
  if (b64pad) while ((ret.length & 3) > 0) ret += b64pad;
  return ret;
}

function base64UrlEncode(s){
  var val = hex2b64(s);

  val = val.replace(/=/g, ''); // Remove any trailing '='s
  val = val.replace(/\+/g, '-'); // '+' => '-'
  val = val.replace(/\//g, '_'); // '/' => '_'

  return val;
}

function hash(value) {
  var hash = Sha256.hash(value);
  return base64UrlEncode(hash);
}

function computeSessionStateHash(clientId, origin, sessionId, salt) {
  return hash(clientId + origin + sessionId + salt);
}

function calculateSessionStateResult(origin, message) {
  try {
    if (!origin || !message) {
      return 'error';
    }

    var idx = message.lastIndexOf(' ');
    if (idx < 0 || idx >= message.length) {
      return 'error';
    }

    var clientId = message.substring(0, idx);
    var sessionState = message.substring(idx + 1);

    if (!clientId || !sessionState) {
      return 'error';
    }

    var sessionStateParts = sessionState.split('.');
    if (sessionStateParts.length !== 2) {
      return 'error';
    }

    var clientHash = sessionStateParts[0];
    var salt = sessionStateParts[1];
    if (!clientHash || !salt) {
      return 'error';
    }

    var currentSessionId = getBrowserSessionId();
    var expectedHash = computeSessionStateHash(clientId, origin, currentSessionId, salt);
    return clientHash === expectedHash ? 'unchanged' : 'changed';
  }
  catch (e) {
    return 'error';
  }
}

var cookieNameElem = document.getElementById('cookie-name');
if (cookieNameElem) {
  var cookieName = cookieNameElem.textContent.trim();
}

if (cookieName && window.parent !== window) {
  window.addEventListener('message', function(e) {
    if (window === e.source) {
      // ignore browser extensions that are sending messages.
      return;
    }

    if (typeof e.data !== 'string') {
      return;
    }

    var result = calculateSessionStateResult(e.origin, e.data);
    e.source.postMessage(result, e.origin);
  }, false);
}
